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Re: Proposal to drop disjunction requirement

From: Dan Connolly <connolly@w3.org>
Date: Fri, 01 Oct 2004 16:15:11 -0500
To: Steve Harris <S.W.Harris@ecs.soton.ac.uk>
Cc: DAWG public list <public-rdf-dawg@w3.org>
Message-Id: <1096665310.5269.300.camel@dirk>
On Fri, 2004-10-01 at 13:21, Steve Harris wrote:
> On Fri, Oct 01, 2004 at 01:22:24 -0400, Kendall Clark wrote:
> > 
> > On Fri, Oct 01, 2004 at 06:17:16PM +0100, Steve Harris wrote:
> > 
> > > conjunctive ones, but it explodes the number of queries needed
> > > dramatically.
> > 
> > In cases where the implementation strategy is based on RDBMS/SQL or in
> > every case? I genuinely don't know.
> 
> In every case - the algorithm prduces a number of prurely conjunctive
> expressions from a mixed dis/con-juntive one.

Really? I can't think of an algorithm for the simplest case:

 (<book1> dc:title "War and Peace") OR (<book2> tc:title "Moby Dick")

Oh.. you mean you turn it into *multiple* queries. Maybe I see.

Don't you need negation in some cases?

[...]
> > I can't imagine
> > ordinary folks writing them.
> 
> Bear in mind that those are the /exact/ translations, the optional
> expression users really write are the natural ones and dont have the hairy
> disjuntive value constraints.

That seems to be the most relevant point/question, to me: do we
expect users to find the optional constructs straightforward for 80%
to 95% of the cases? Or do we expect them to say "hey; where's the OR
thingy?" in their first week of usage?

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E

Received on Friday, 1 October 2004 21:15:05 GMT

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